Beirut: UN Secretary-General Kofi Annan called Israel's latest attack on Lebanon a violation of the UN backed truce that ended the 34-day war.

"The secretary-general is deeply concerned about a violation by the Israeli side of the cessation of hostilities as laid out in Security Council resolution 1701," a spokesman for Annan said in a statement posted on the United Nations Web site.

Annan called on all parties "to respect strictly the arms embargo, exercise maximum restraint (and) avoid provocative actions".

Lebanese security sources said Israeli helicopters unloaded two vehicles carrying commandos who headed towards an office of a Hezbollah leader, Shaikh Mohammed Yazbek, in Bodai, 26km from the Syrian border.

The Israelis were intercepted and withdrew under cover of air strikes, they said.

The sources said three Hezbollah guerrillas were killed in a firefight with the Israelis, although Hezbollah said none of its fighters were killed or wounded.

Israel denied violating the UN resolution saying that the operation was defensive and designed to disrupt weapons supplies to Hezbollah from Syria and Iran. Israel said it was actually Hezbollah who had violated the ceasefire by smuggling weapons.

Senior United Nations envoy Terje Roed-Larsen said that if Hezbollah was found to have smuggled weapons, it would be in breach of the truce.

During discussions with Annan, Lebanese Prime Minister Fouad Siniora said the operation was "a naked violation of the cessation of hostilities declared by the Security Council", whilst Israeli Prime Minister Ehud Olmert "pointed out the importance of supervision of the Syrian-Lebanese border."